Re: [RFC PATCH 03/21] x86/virt/tdx: Add SEAMCALL wrapper tdh_mem_page_demote()

[Binbin Wu]

On 4/25/2025 3:17 PM, Yan Zhao wrote:
> On Fri, Apr 25, 2025 at 03:12:32PM +0800, Binbin Wu wrote:
> > On 4/24/2025 11:04 AM, Yan Zhao wrote:
> > > From: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> > >
> > > Add a wrapper tdh_mem_page_demote() to invoke SEAMCALL TDH_MEM_PAGE_DEMOTE
> > > to demote a huge leaf entry to a non-leaf entry in S-EPT. Currently, the
> > > TDX module only supports demotion of a 2M huge leaf entry. After a
> > > successful demotion, the old 2M huge leaf entry in S-EPT is replaced with a
> > > non-leaf entry, linking to the newly-added page table page. The newly
> > > linked page table page then contains 512 leaf entries, pointing to the 2M
> > 2M or 4K?
> The 512 leaf entries point to 2M guest private pages together,
If this, it should be 2M range, since it's not a huge page after demotion.
Also, the plural "pages" is confusing.

>   each pointing to
> 4K.
>
> > > guest private pages.